A digital network comprises of a group of switches that are connected to each other through a variety or interfaces. Asynchronous Transfer Mode (“ATM”) or “cell switching” is a technology designed for transmitting digital information such as voice, video, and data at high speeds through the digital network. The digital information is transferred by first being broken into equal sized units called cells. The cells are then transmitted from node to node until they reach a destination node through a pathway (or connection) in the digital network.
The digital network is constructed of digital switches coupled together by digital communication links such as trunks. These trunks carry the cells of information between the digital switches along the connection. The digital switches route the cells from incoming communication links to outgoing communication links and finally to the destination node.
The trunks in the digital network vary in size with each trunk size capable of handling a certain amount of bandwidth. The trunk's bandwidth handling capability determines the amount of traffic that can be channeled through the trunk at any one time. In a communication, such as a call, between the destination node and an initial node each trunk being utilized for channeling the communication is requested to set aside an amount of bandwidth requested by the client setting up the communication for completion of a call. In many instances the client requesting the allocation of bandwidth per call does not use all of the requested bandwidth at any one time. This wastes valuable trunk space by having the trunk tied up with a requested bandwidth allocation that is being underutilized.
One prior art solution attempts to overcome the wasting of trunk resources. The solution involves manually programming each trunk to allocate an amount of bandwidth lower than the bandwidth requested by the client. This is known as static overbooking. With static overbooking, a Private Network-to-Network Interface (“PNNI”) controller is configured to provide overbooking per interface and service category. Because the client does not use all of the requested bandwidth, allocating an amount less than the requested amount leaves the unused portion available for use for other calls. A related prior technique is static underbooking, which involves programming each trunk to allocate an amount of bandwidth higher than the bandwidth requested by the client.
Nevertheless, the fact that ATM networks typically include numerous nodes and trunks places a limitation on the prior art static overbooking and underbooking approaches. Because there are numerous nodes available, numerous paths may be constructed using these nodes. Because path construction depends upon the availability of network resources at the time a call is placed, it is difficult to determine which path and therefore which nodes and trunks may be used for any particular call. Not knowing in advance which path a call may take makes it difficult to program every trunk in the network.
Yet another problem with prior art static overbooking or underbooking is that each manual programming task would have to be repeated for a subsequent call. Because client requests for bandwidth allocation change over time and may change for each call placed by the client, the manual configuration would have to be performed every time a change is made. This approach is inefficient, costly, and can results in delays.
Yet another problem with manual configuration is that it does not allow for system monitoring. Typically network resources and client requests and usage of resources change frequently and would need to be monitored and updated for maximizing trunk capacity. Manual configuration without any monitoring does not provide the gathering of data for updating trunk bandwidth allocations and therefore is an inefficient approach.